Further steps into dentistry. Учебное пособие для студентов стоматологического факультета

Defects in Enamel or Tooth Color

A dead tooth appears gray. Darkening of the teeth and enamel hypoplasia follow chronic administration of tetracyclines during the second half of pregnancy or during tooth development in the child. The affected teeth, rather than fluorescing white in ultraviolet light, have a colored fluorescence characteristic of the type of tetracycline given. A dark band may be visible in ordinary light after only 5 days of therapy. A generalized yellowish or brownish discoloration is often seen in smokers. Users of smokeless tobacco develop such changes in the area where the quid is held. The abnormal calcium metabolosm associated with rickets results in enamel hypoplasia. A rough, irregular band appears around each tooth. The location of the band indicates the area being calcified at the time of abnormal calcification, thus providing an estimate of the age at which the disease occurred and its duration. Such teeth are not unduly susceptible to dental caries. A high fever during odontogenesis can also interfere with enamel formation, and a marrow zone of chalky, pitting enamel is visible after the tooth erupts. Amelogenesis imperfecta, an autosomal dominant hereditary disease, causes severe enamel hypoplasia. Decalcification of dental crowns occurs with chronic vomiting, as a bulimia (the lingual surfaces of the lower anterior teeth being primarily affected), and with cocaine use. Chronic snorting followed by salivary dissociation of the drug into the base hydrochloride, often abetted by massage of the oral mucosa to hasten absorption, results in widespread decalcification of teeth. Development of rampant caries after childhood may indicate chronic use of marijuana, which is often accompanied by a craving for sweets and inattention to oral hygiene. Children who drink water containing > 1 ppm of fluoride during the period of tooth development are likely to develop mottled enamel (fluorosis). The enamel changes can range, depending on the amount of fluoride ingested, from irregular whitish opaque areas to severe brown discoloration of the entire crown, with a roughened surface. Such teeth have a high resistance to dental caries. In congenital porphyria, teeth fluoresce a reddish color from deposition of pigment in the dentin.

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Rampant Caries of Deciduous Teeth

It frequently indicates that the teeth had been in prolonged contact with a sweetened infant formula, perhaps while the infant napped («nursing bottle caries»). To minimize the prevalence of caries, oral drugs should not be chronically administered to children in a metabolizable sugar-based vehicle.

With age, teeth darken and biting surfaces become worn (attrition) so that chewing is less effective. Gingivae may recede , thus exposing more of the crowns and often even part of the roots. Since a small zone of exposed dentine is sensitive to touch or temperature alterations, noncarious can become painful when enamel and cementum do not quite contact each other. The dentist can desensitize such teeth. Proper keratinization of the oral mucosa requires sex hormones. Hormonal therapy can ameliorate the poorly keratinized, inflamed mucosa commonly found after menopause. In edentulous jaws of elderly persons, atrophy of the alveolar process (senile atrophy) is common. This diminished the stability of an artificial full denture, particularly the lower one. Oral surgical procedures can improve the situation.

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Normal Occlusion

Occlusion should be checked on both sides of the month; this can be done by retracting each cheek with a tongue depressor while the patient bites normally. In normal occlusion, the maxillary anterior teeth overlie the mandibular anterior tooth. The outer (buccal) cusps of the maxillary posteriors are external to corresponding cusps of the mandibular posterior teeth. Since the outer parts of all the maxillary teeth are superficial to the mandibular teeth, the lips and cheeks are displaced from between the teeth so they are not bitten. Furthermore, the lingual (inner) surfaces of the lower teeth are in a smaller arc than that of the upper teeth, containing the likelihood of its being bitten as the teeth occlude. All the teeth should contact their opponents, so that the powerful masticatory forces (which may be > 100 lb in the molar region) are widely distributed. If these forces are applied to only a few teeth, those teeth are likely to loosen.

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Malocclusion

The most common classification of deviation from the normal contact of the maxillary and mandibular teeth identifies 3 major forms of malocclusion. Class 1: The upper and lower molars occlude normally, but the anterior teeth are crowded or malpositioned. Class II: The lower jaw retracts and the facial profile is complex. Class III: The mandibular protrudes. Etiology: Maloccusion often reflects a disproportion between jaw and tooth size - ie, a jaw so small or teeth so large that the jaw cannot accommodate them all in proper alignment. Other causes are supernumerary, malformed, or missing teeth; delayed eruption or impaction of permanent teeth; ankylosis of the mandible; cleft lip or palate; and rarely; cleidocranial dysostosis or Hurler’s syndrome. A frequent cause of acquired malocclusion is loss of teeth with shifting of adjacent teeth and extrusion of opposing teeth unless a bridge or partial denture is worn. Premature loss of deciduous teeth in children often results in approximation of adjacent teeth, causing insufficient space for eruption of the permanent successors. This shift can be prevented by a dental appliances termed a space maintainer. Less frequently, malocclusion results from habits such as thumband finger-sucking or tonguethrusting. Iatrogenic malocclusion can occur from improper dental restorations and appliances, improper fixation of jaw fractures, or a Milwakee orthopedic back brace, which places constant pressure on the mandible. Rarely, teeth are displaced by an underlying jaw tumor.

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cleidocranial dysostosis – клю- iatrogeniс – ятрогенный, нечичночерепной дизостоз (деблагоприятный эффект, выфект развития), характеризузванный лечебными мероприющийся отсутствием или руятиями

диментарным развитием клю- orthopedic brace – фиксируючиц, ненормальной формой щее устройство, ортопедичечерепа с вдавлением сагитская скоба тального шва, лобных бугров, шовных костей черепа, аплазией или гипоплазией зубов

Diagnosis and Treatment

Malocclusions are corrected primarily for oral health reasons, although the patient often needs help for cosmetic or psychologic reasons. Because early interceptive orthodontics usually eliminates a later need for more expensive and difficult technique, a child should have a dental consultation as soon as malocclision is suspected. The evaluation indicates x-rays of the skull, facial bones, and study casts of the teeth. Malocclusion following facial trauma may suggest tooth displacement or trauma, often accompanied by a jaw fracture.

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препятствующие, задерживаюбов и челюстей) щий, перехватывающий

Therapy

Therapy increases resistance to dental decay, anterior tooth-edge fracture, and periodontal disease, and it improves speaking and mastication. Occlusion can be improved by selective grinding where teeth or restorations contact prematurely, by aligning teeth properly, or by inserting crowns or onlays to build up teeth that are below the plane of occlusion. Applying a continuous mild force to the teeth by means of orthodontic appliances (braces) moves the teeth

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by gradually remodeling the alveolar bone. Some patients initially require extraction of 1 or more permanent teeth to obtain enough space for stable alignment. When the final relationship has been achieved, the patient wears a plastic retainer at night until the teeth stabilize in new position. When it is anticipated that treatment may not suffice, surgical correction of jaw abnormalities contributing to malocclusion (orthognathic surgery) is often indicated. Orthodontic treatment of adults is now commonplace.

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Oral Mucosa

The patient should be asked to remove dentures so that the underlying soft tissues may be seen. The likelihood of dropping or distorting a dental appliances is greater if the physician attempts to remove it.

With a finger cot for protection against infectious lesions, the examiner palpates the cheek bimanually (with one finger inside and one outside) to delimit lesions. Most people have yellowish, pinhead-size maculae in the buccal mucosa. These are harmless ectopic sebaceous glands (Fordyce’s granules). Many persons have a thin white line (linea alba) on the buccal mucosa along the occlusal plane. It represents surface keratinization due to accidental, repeated check biting over the years. The color of soft tissues can reflect anemia, polycythemia, cyanosis, or jaundice. One looks for generalized inflammation (stomatitis) as well as localized area of inflammation, ulceration, petechiae, or thickening. Darkly pigmented areas may indicate a racial characteristic, Addison’s disease, or very rarely, melanoma. Violaceous Kaposi’s sarcoma is a common intraoral finding in AIDS.

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Dryness of the mouth may be from dehydration, mouth breathing, or use of diuretics or anticholinergics, or may reflect salivary gland dysfunction or disease. The orifices of the parotid ducts open in the cheek beside the maxillary molar. The sublinqual and submandibular salivary gland open on the floor of the mouth behind the lower incisors. When pain or swelling occurs in one of those regions and saliva does not emanate, the duct may be obstructed by a calculus (sialolith).

The distribution of keratinized and nonkeratinized oral mucosa can be significant. Keratinized epithelium is on the facial aspect of the lips, the dorsum of the tongue, the gingiva around the base of the dental crowns and adjacent part of the roots of the teeth, and on the hard palate. It is less likely to be damages by hard particles than nonkeratinized mucosa that is mobile, as in the cheek, sides of the tongue, soft palate, and floor of the mouth. Keratinized mucosa in these areas is abnormal, and a definite diagnosis must be made. White areas may be seen in the mucobuccal fold in adolescents or other who retain snuff or chewing tobacco there.

Such leukoplakias may be precancerous. Type I herpes simplex eruptions occur on the keratinized mucosa, while the lesions of aphthous stomatitis occur on the nonkeratinized mucosa. In some

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тём вдыхания через нос или филов в циркулирующей крови нанесения на дёсны

Gingiva

The gum should be firm and nicely contoured about and adapted to the crowns of the teeth. Pink, slipped tissue should fill the entire interdental space. Keratinized gingiva is present near the crown. More distant gingiva is nonkeratinized, highly vascular, and continuous with the buccal mucosa. A tongue depressor should express no blood or pus from the gingiva. At the gingival margin, a dark line suggests exposure to lead or some other heavy metal. Gingivitis is common. Gingival fibromatosis may be idiopathic but often seen with chronic administration of phenytoin, cyclosporin, or nifidipin. Some patients with regional enteritis have an area of granulomatous gingival hypertrophy that becomes symptomatic with intestinal flare-ups. Widespread gingivitis with only minimal dental calculus (tartar) could indicate a systemic disease (eg, scurvy, diabetes mellitus, leukocyte disorders). Local infection about the teeth predisposes to bacteremia during brushing, dental procedures, and oral surgery.

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The Palate

The anterior portion of the hard palate is the site of the incisive papilla adjacent to the central incisiors. Behind it are the rugae, firm ridges that keep from slipping as the tongue crushes the food against them. A person with a cleft palate has a very nasal voice. Normal vocal resonance and articulation involve the anterior teeth, lips, and palate, as well as the lungs, vocal cords, and pharynx. A very high palatal vault is seen in Marfan’s syndrome. Punctate areas of inflammation about the ducts of the numerous minor salivary glands of the palate are common, especially in pipe smokers. The boneless soft palate should rise symmetrically when the patient says «ah». The uvula at the far end of the soft palate’s midline varies greatly in length among individuals. A very long uvula, associated with very loud snoring, may be present in persons who have obstructive sleep apnea.

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Tongue and Floor of the Mouth

As the patient touches the tip of his soft palate, one can examine the floor of the mouth and the under surface of the tongue, where cancer often starts. The tongue, having a wide range of movement, should be able to twist its tip around the sides of the molar teeth. Normal tongue movement indicates hypoglossal nerve function, but neuromuscular weakness may prevent its a midline position or moving rapidly. For a neurologic evaluation of taste, 0,1 M solution of NaCI, HCI, sucrose, and urea may be used. The tongue may be enlarged in myxedema, amyloidosis, or acromegaly, or if a rhabdomyoma is present. In edentulous individuals without complete dentures, the tongue tends to broaden.

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The papillae may be normal or atrophied. The tongue is smooth and pale in pernicious anemia or smooth and fiery red in deficiencies of niacin or riboflavin. Oral cancer often occurs on the lateral surface of the tongue. Oral candidiasis or a slightly elevated white area with a corrugated surface (hairy leukoplakia) may indicate AIDS.

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Salivary Glands

Saliva promotes retention of artificial dentures because of its mucin content. Thus, conditions characterized by diminished saliva flow often adversely affect case with which dentures may be worn. If natural teeth are present, salivary flow washes away bacteria and food debris, facilitating oral cleanliness. A reduction in flow or decrease in salivary IgA fosters bacterial growth and development of tooth decay. This may be caused by an abnormality of the salivary glands. Contact with a patient’s saliva should be avoided, even though the risk of transmitting HIV and hepatitis B virus from saliva may be less than that from blood. The risk might be greater if extensive oral lesions, gingivitis, or periodontitis is present, allowing seepage of serum into the mouth.

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